When we tested the Crc Builder on our systems we found the programs worked very quickly, but at a user site it ran very poorly. One of the problems for this was the way we opened the file, we opened the file using the default options which caused the data to be retrieved in the same sequence as it was generated. We are hoping this latest version will help with this as we now open the file for sequential reads…
We have also added the ability to determine the CRC to be generated so it now supports MD5, SHA-1, SHA-256, SHA-384, SHA-512 and ADLER32. ADLER_32 uses the Zlib functionality to generate the CRC instead of the OS/400 API. You can determine the output level by setting the DSPBLK parameter, when set to *YES and you use one of the IBM supported algorithms you will see the CRC for each block of data. Another option is the buffer size setting which can be set to 32K, 64K, 1MB, 4MB or 16MB. This is the amount of data which will be passed each time to the CRC generator. We have experimented with various buffer sizes and not seen any real difference, but you may if you have different amounts of memory availability.
We will continue to develop more capabilities and try to speed up the process as time allows. We have a couple of API’s to check out and further analysis of some of the other fopen() parameters so we hope to squeeze out a lot more speed in future releases.
Here is the latest version..
If you do find any problems please let us know and we will try to develop fixes.